1. Field of the Disclosure
This disclosure relates in general to high work function transparent conductors for use in electronic devices.
2. Description of the Related Art
Organic electronic devices define a category of products that include an active layer. Such devices convert electrical energy into radiation, detect signals through electronic processes, convert radiation into electrical energy, or include one or more organic semiconductor layers.
Organic light-emitting diodes (OLEDs) are organic electronic devices comprising an organic layer capable of electroluminescence. OLEDs containing conducting polymers can have the following configuration;
anode/buffer layer/EL material/cathode
Additional, optional layers, materials or components may be incorporated into this general configuration. The anode is typically any material that has the ability to inject holes into the electroluminescent (“EL”) material, such as, for example, indium/tin oxide (ITO). The anode is optionally supported on a glass or plastic substrate. The buffer layer is typically an electrically conducting polymer and facilitates the injection of holes from the anode into the EL material layer. EL materials include fluorescent compounds, fluorescent and phosphorescent metal complexes, conjugated polymers, and mixtures thereof. The cathode is typically any material (such as, e.g., Ca or Ba) that has the ability to inject electrons into the EL material. At least one of the anode or cathode is transparent or semi-transparent to allow for light emission.
ITO is frequently used as the transparent anode. However, the work function of ITO is relatively low, typically in the range of 4.6 eV. This results in less effective injection of holes into the EL material. In some cases, the work function of ITO can be improved by surface treatment. However, these treatments sometime result in products that are note stable and further result in reduced device lifetime.
Accordingly, there is a need for compositions and layers prepared therefrom to improve the properties of the device.